Methods and systems for providing accessory steering wheel controls

ABSTRACT

An aftermarket steering wheel control includes a housing that includes a user-operable switch and a control module. The control module is configured to determine whether the user-operable switch has been operated, generate a data frame corresponding to a control signal for operating a vehicle component, and transmit the data frame to a receiver of a control signal interface. Another aftermarket steering wheel control includes a housing with a user-operable switch and a circuit with an output line. The output line is connected to the switch and further connected to a control signal interface. Operation of the user-operable switch changes a resistance on the at least one output line, and the control signal interface is configured to convert the resistance to a control signal for operating a vehicle component.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/545,429, which was filed on Aug. 21, 2009, the full contentof which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to steering wheel controls for avehicle. More specifically, the invention relates to aftermarketsteering wheel controls that can provide control signals to a steeringwheel control interface.

2. Description of the Related Art

Vehicle owners often seek to replace factory-installed audio and videocomponents with aftermarket components. These aftermarket componentsoften must be hard-wired to a vehicle's factory wiring. This may requirethat a user connect various power, audio, and video wires, and furtherthat the aftermarket component communicate and operate, in part, throughsuch wiring. Many modern vehicles include controls on their steeringwheels for operating factory-installed components. These steering wheelcontrols (SWC) may, for example, increase the volume of a radio,increase the track of a CD being played, or change from one audio sourceto another. However, the particular configuration of a vehicle'ssteering wheel controls differs significantly among vehicle makes,models, and model years. Accordingly, it is very difficult formanufacturers of aftermarket components to provide compatibility betweentheir components and the wide array of steering wheel controlconfigurations.

U.S. Pat. Nos. 7,020,289 and 6,956,952 describe hard-wired interfacesfor handling SWC signals. A commercial product similar to suchinterfaces is a SWI-JACK interface manufactured by the Pacific AccessoryCorporation (PAC). The SWI-Jack interface has a wire harness on an inputside and an output plug on an output side. To install the input side, aninstaller first selects a particular wire from among many included onthe wire harness. The selection is made based upon a lengthy chart,which indicates suitable wires for particular vehicle makes and models.Once selected, the installer electrically connects the selected wire toa steering wheel audio control wire, which provides an output signalfrom the steering wheel audio controls. The SWI-JACK interface is gearedto audio control wires provided within the steering column or underneaththe vehicle's dashboard. To install the output side, the installercouples the output plug to a wired remote-control input on anaftermarket head-unit. Once the input and output sides have beeninstalled, the installer completes installation by adjusting an inputswitch on the SWI-JACK. The adjustment is made according to themanufacturer of the aftermarket head unit.

There are several drawbacks to an interface such as the SWI-JACK. First,the interface is not designed to function upon installation. Rather, theinstaller must perform a lengthy programming process, with pressing andreleasing the respective buttons on the steering wheel controlsaccording to an installation sequence. The process is not only lengthy,but unforgiving. If the installer does not correctly perform thesequence, he must start the sequence over. Second, there can be severalwires provided within a vehicle's steering column or dashboard. As aresult, the installer may choose the wrong wire when attempting toelectrically connect the interface to the steering wheel audio controlwire. This could permanently damage components within the vehicle andcompromise vehicle safety. A related drawback results from requiring theinstaller to choose a particular wire from the many wires of the wiringharness: if the installer selects the wrong wire from the harness,damage or malfunction to either the SWI-JACK or the vehicle can result.Furthermore, an inherent drawback of passive component interfaces, suchas the SWI-JACK, is that they are compatible only with a limited numberof manufacturers of aftermarket radios.

Another type of interface incorporates wireless transmission to relaySWC signals to the aftermarket component. Products manufactured withthis design include the SWI-X interface by PAC and the REMOTE seriesinterface by SoundGate. Generally speaking, these interfaces have a wireharness and an infrared (IR) receiver on an input side, and an IRtransmitter on an output side. Installation of the input side proceedsin a manner similar to that described above in connection with theSWI-JACK. Installation of the output side involves mounting and aimingthe IR transmitter such that it can communicate with an IR receiverintegrated with the aftermarket component.

This design has several limitations, one of which is the lengthyprogramming process. The input and output sides having been installed,the installer must perform a wireless remote control “learning” process.For each steering wheel audio control button, the installer must use theremote control provided with the aftermarket component to emit an IRsignal to the interface's IR receiver. The interface then “learns” theIR signal and stores its signal format for future reproduction, similarto a process used in learning television remote controls. The interfacecannot reproduce an IR signal according to the steering wheel audiocontrol inputs until this learning process has been performed.

The wireless interface design also fails to overcome the drawbacks ofthe SWI-JACK interface. The installer must connect the appropriatesteering wheel audio control wire, risking permanent damage andmalfunction to the vehicle and the interface. And if the installerincorrectly performs any part of the programming process, he must startover, leading to frustration.

Some methods of communication between a vehicle's electrical componentsare known. U.S. Pat. Nos. 7,275,027, 6,114,970, 6,823,457, 6,141,710,and 6,396,164 describe interconnections between a factory-configuredvehicle bus (OEM bus) and a device bus for aftermarket products andaccessories. These interconnections generally use a gateway controller.However, in these devices, the vehicle and device bus structures arepre-determined. In this configuration, the gateway controller merelytranslates between a single set of OEM bus commands and a single set ofdevice bus commands. Thus, these gateway controllers are tied to aspecific vehicle bus and/or device bus architecture. Accordingly, theyare inapplicable to universal aftermarket products.

As the above discussion makes clear, there is a need to provide asimple, universal solution for providing SWC inputs of all makes andmodels to aftermarket radios from a wide variety of manufacturers. Inparticular, an installer can benefit from a device which automaticallydetects at its input an SWC signal and which configures itselfaccordingly. Additionally, installers can further benefit from a devicewhich automatically detects an aftermarket component and which furtherconfigures itself accordingly. In this manner, the device allows for asimple “plug-and-play” installation process, reducing the stress andrisks of installation for both professional and self-installers.

Installation of a device that automatically configures itself inresponse to detected SWC signals nevertheless may not provide somevehicle owners with the capability to control their aftermarketcomponents via steering wheel controls. As discussed above, manyvehicles include factory-installed SWC, as well as other on-wheelcontrols, such as those for controlling the vehicle's cruise control,and steering column controls, such as those for controlling thevehicle's turn signals or windshield wipers. (As used herein, the phrase“steering wheel component” and “SWC” refers to both kinds ofcomponents.)

Some vehicles, however, may not include factory-installed steering wheelcomponents that are suitable for use in sending SWC signals. This may bethe case, for example, where steering wheel stereo controls are optionalequipment on a vehicle and the purchaser did not opt to have thecontrols installed, or where the vehicle is an older model manufacturedprior to steering wheel stereo controls being offered as standard oroptional equipment. In cases such as these, after a vehicle owner or aninstaller installs an aftermarket stereo, the owner remains unablecontrol the stereo via steering wheel controls because, simply put, theowner has no suitable SWC components. Or, if the user does have somesteering wheel components, these components nonetheless may not bereconfigurable to transmit SWC signals. For example, where a vehicle'sonly steering wheel components are a turn signal and windshield wipercontrols, even were the user able to reconfigure these components tocontrol the aftermarket stereo, doing so would cause the vehicle to losethe functions of the turn signals and windshield wipers.

Some known aftermarket components add certain functionality to avehicle's steering wheel. For example, the Scosche IPNRFCR remotecontrol, which attaches to a steering wheel, can be used to control anApple iPod. Similarly, the Pioneer CD-SR100 and Blaupunkt RC-10 remotecontrols may be used to directly control aftermarket stereos made bythose manufacturers. However, these components are configured tocommunicate with a specific aftermarket stereo; none appear to be ableto communicate with a device that provides SWC inputs to variousaftermarket radios.

Accordingly, there is an additional need for an aftermarket componentthat provides the owner of a vehicle with steering wheel controls havingsuitable SWC inputs for an SWC interface, regardless of which, if any,steering wheel components are factory-installed in the vehicle.

SUMMARY OF THE INVENTION

The present invention addresses the challenges in the art discussedabove.

According to one aspect of the invention, an aftermarket steering wheelcontrol includes a housing and a control module. The housing includesone or more user-operable switches. The control module is configured todetermine whether the any switches have been operated (e.g., whether theuser has pressed a button on the housing). If so, the control modulegenerates a data frame that contains data corresponding to an operatingcommand for a vehicle component (e.g., an aftermarket stereo), andtransmits the data to a SWC interface. Accordingly, a user may operatethe switches in the housing to send SWC signals to the SWC interfaceand, ultimately control the vehicle component.

According to another aspect of the invention, an aftermarket steeringwheel control includes a housing and a circuit. The housing includes oneor more user-operable switches. The circuit includes one or more outputlines that connect the switches to a SWC interface. By virtue of thecircuit's configuration, operation of the switches results in a changein resistance on the output lines. The SWC interface is configured toconvert the resistance into a control signal for operating a vehiclecomponent.

Further features and advantages, as well as the structure and operation,of various example embodiments of the present invention are described indetail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the example embodiments of the inventionpresented herein will become more apparent from the detailed descriptionset forth below when taken in conjunction with the drawings. Likereference numbers between two or more drawings can denote identical orfunctionally similar elements unless the description indicatesotherwise.

FIG. 1 shows a top-level block diagram of a device suitable for use invarious embodiments of the invention.

FIG. 2A shows a top-level block diagram of an example circuit accordingto one aspect of the invention.

FIG. 2B shows a top-level block diagram of another example circuitaccording to the same aspect of the invention as illustrated in FIG. 2A.

FIG. 2C shows a top-level block diagram of an example circuit accordingto another aspect of the invention.

FIG. 3 shows a top-level block diagram of an example circuit accordingto still another aspect of the invention.

FIG. 4 illustrates a method of installing and configuring a deviceaccording to various embodiments of the invention.

FIG. 5 shows a method of auto-detecting a vehicle configuration and anaftermarket component according to an embodiment of the invention.

FIG. 6A shows a method of manually configuring an SWC interface.

FIG. 6B shows another method of manually configuring an SWC interface.

FIG. 7 shows a block diagram of an example aftermarket steering wheelcontrol configured together with an example SWC interface.

FIG. 8 shows a block diagram of an example aftermarket steering wheelcontrol.

FIG. 9 shows a block diagram of an example SWC interface.

FIG. 10 shows a schematic diagram of an example circuit in anaftermarket steering wheel control.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

As described above, various aspects of the invention provide for SWCinterfaces that can automatically detect factory-installed andaftermarket components and buses.

Vehicles may transmit signals from a steering wheel to variousfactory-installed components in various ways. The method of transmissioncan vary among vehicle makes and models. One common method is a variableresistance method. In this method, the steering wheel component can be,for example, a button provided with an arrangement of switches andresistors. Operation of the button by pressing closes or opens a switch.In turn, this operation changes the resistance on an output line. Theoutput line is wired to a factory-installed component, such as an OEMradio. The variable resistance is fed into the component, which decodesthe resistance and translates the change in resistance into theoperation of the steering wheel button.

Another common method is to use a data bus. This method, which is commonin many modern vehicles, incorporates a data bus architecture to sendsignals and commands among the various electrical components of avehicle. Known architectures include J1850, CAN-BUS, and K-BUS. In thismethod, circuitry is coupled to a steering wheel button. This circuitrytransmits digital signal commands along the data bus when the button ispressed. The OEM radio monitors the data bas for the commands. Operationof the radio is controlled according to commands received by the radioover the bus.

As noted above, the transmission of SWC signals from steering wheelcomponents can vary from vehicle to vehicle. An auto-detection methodsuitable for an individual vehicle thus can depend, broadly speaking, onthe method of transmission used in that vehicle, and, more specifically,on the particular electronic configuration of its steering wheelcomponents. Accordingly, one aspect of the invention provides methodsfor auto-detecting SWC signals among many makes and models of vehicles.These methods will now be described.

In a vehicle where SWC signals are transmitted by a variable resistancemethod, the SWC signals can be auto-detected by measuring characteristicvoltages or other electronic properties associated with that vehicle'sSWC components. In many vehicles configured according to a variableresistance method, SWC signals are transmitted on channels configuredwith a standby resistance. That is, even when no SWC signal is beingtransmitted on a channel—as may be the case when, for example, the“volume up” steering wheel button is not depressed—a small electricalcurrent nonetheless is drawn by the standby resistance. In theseinstances, an SWC interface can be configured to measure, for example, acharacteristic voltage exhibited by the channel. This voltage can bemeasured by the SWC interface using, for example, a resistor pulled upto a suitable voltage, such as 5 V or 12 V, depending on the particularSWC configuration of the vehicle, or a resistor pulled down to ground.To measure the characteristic voltage, a resistor pulled up to asuitable voltage may be used when a vehicle's standby resistance ispulled down to ground, while a resistor pulled down to ground may beused when a vehicle's standby resistance is pulled up to a particularvoltage.

The following examples illustrate the principle of a characteristicvoltage. Consider two hypothetical vehicles, A and B, each having an SWCchannel that transmits a “volume up” signal. In vehicle A, the channeloperates between 0 V and 5 V and has a standby resistance of 6 kΩ thatpulls down to ground. In vehicle B, the channel operates between 0 V and5 V and has a standby resistance of 24 kΩ that pulls down to ground. Ifan SWC interface with a pull-up resistance of 1 kΩ is connected to thechannel of vehicle A, the voltage in front of the pull-up resistancewill be 4.29 V. Thus, 4.29 V is a characteristic voltage of the volumeup channel of vehicle A. On the other hand, if an SWC interface with apull-up resistance of 1 kΩ is connected to the channel of vehicle B, thevoltage in front the pull-up resistance will be 4.80 V. Thus, 4.80 V isa characteristic voltage of the volume up channel of vehicle B.

In some embodiments of the invention, the SWC signals of a particularvehicle can be auto-detected based on the characteristic voltage ofindividual SWC channels. In this aspect of the invention, an SWCinterface can be electrically connected to the channels of a vehicle'ssteering wheel components. Because each SWC channel of a particularvehicle may a characteristic voltage, patterns among the characteristicvoltages of the channels can be used by the SWC interface. For example,a particular vehicle manufacturer may configure its vehicles such thateach SWC channel has a characteristic voltage of 4.29 V when measured bya pull-up resistance of 1 kΩ. Another manufacturer may configure itsvehicles such that each SWC channel has a characteristic voltage 4.80 Vwhen measured by a pull-up resistance of 1 kΩ. Yet another manufacturermay configure its vehicles such that each SWC channel has acharacteristic voltage of 1.20 V when measured by a pull-down resistanceof 4.7 kΩ. Those having skill in the art will recognize that there aremany patterns possible, and that such patterns may vary depending on,for example, a vehicle's make, model, and year. A configuration of anSWC interface suitable for auto-detecting SWC signals transmitted over avariable resistance network is discussed below in connection with FIGS.2A and 2B.

Although some embodiments directed to auto-detecting a vehicle'svariable resistance network may utilize electrical currents drawn by astandby resistance, the invention does not require a standby resistanceto be operable. For example, the SWC channels in some vehicles do nothave a detectable standby resistance. In this instance, auto-detectionmay proceed in conjunction with an instruction to an installer tooperate one or more SWC components, e.g., the installer may beinstructed to press and hold an SWC volume up button for the duration ofthe detection phase.

Turning now to vehicles where SWC signals are transmitted by a data busmethod, SWC signals can be auto-detected by determining a particularvehicle's bus type from among known communication protocols. In vehiclesconfigured with a data bus, data bits are transmitted on the bus at apredetermined frame rate. The frame rate of a particular bus can dependon the communication protocol used by the bus. Thus, different bussesmay transmit data bits at different frame rates. For example, GeneralMotors' GMLAN bus transmits frames at 33.33 kb/s, while Chrysler's CANbus transmits frames at 83.33 kb/s. Thus, by determining thetransmission rate of a vehicle's bus, the SWC interface also candetermine the type of data bus used in the vehicle. Because data bustypes among vehicle manufacturers are often highly proprietary, adetermination of bus type can be sufficient to allow a designer of anSWC interface to configure the interface to differentiate among signalstransmitted on the data bus and to decode individual SWC signals.

In some embodiments of the invention, SWC signals of a particularvehicle can be auto-detected based on a determination of a communicationprotocol of the vehicle data bus. In these embodiments, an SWC interfacecan be electrically connected to the data bus by, for example, a jack, aplug, or manual connection of electrical wires. In some vehicles,connecting an SWC interface and providing electrical power to thevehicle can be sufficient to allow the SWC interface to auto-detect SWCsignals. This is because some vehicles transmit SWC data frames evenwhen no steering wheel component is being operated, e.g., when no buttonis depressed. Thus, there are embodiments in which an SWC interface candetermine the frame rate of the vehicle's data bus without any manualoperation of a steering wheel component. In other vehicles, however, asteering wheel component may need to be operated in order to have dataframes transmitted on the bus and to allow for a determination of theframe rate. Auto-detection of SWC signals in these vehicles may requiremanual operation of one or more steering wheel components. For example,an installer may need to press a steering wheel button at one-secondintervals during an auto-detection process performed by the SWCinterface. A configuration of an example SWC interface suitable forauto-detecting SWC signals transmitted on a vehicle bus is discussedbelow in connection with FIG. 2C.

There are some embodiments of the invention in which an SWC interface iselectrically connected to variable resistance network, and there areother embodiments in which an SWC interface is electrically connected toa vehicle data bus. However, the invention is not limited to oneelectrical connection or the other; in some embodiments an SWC interfacecan connect both to a vehicle's variable resistance network and to thevehicle's data bus. In these embodiments, an auto-detection process canproceed according to information gained from both connections, as willbe recognized by those having skill in the art. For example, although aconnection to a variable resistance network may yield characteristicvoltages of that network, this information may not be sufficient toauto-detect the vehicle's SWC signals. That is, any pattern identifiedin the characteristic voltages may not be sufficiently unique toconfigure an SWC interface. However, a connection to the vehicle bus canallow an SWC interface to determine other information besides a dataframe rate, such as the vehicle's unique vehicle identification number(VIN). This information obtained from the data bus, together with thepattern of characteristic voltages, may be sufficient to allow the SWCinterface to auto-detect SWC signals. Thus, the auto-detection processcan be performed using both connections, where one connection or theother may not have been sufficient.

FIG. 1 shows a top-level block diagram of an SWC interface according toan embodiment of the invention. SWC interface 10 includes an input side11 and an output side 13. Input side 11 can include one or morecomponents configured to auto-detect SWC signals that are transmittedfrom a steering wheel component 14 or on a vehicle bus 16. Specificfeatures of input side 11 are discussed below in connection with FIGS.2A-C. Output side 13 includes one or more components configured toauto-detect aftermarket component 18 and further configured to deliverSWC signals to aftermarket component 18. Examples of aftermarketcomponent 18 include an audio component (e.g., a radio receiver/tuner, acassette tape player, a CD player, a MiniDisc player, an amplifier, anequalizer, or a digital signal processor), a video component (e.g., avideo display, a television display, a VHS player, or a DVD player), anavigational component (e.g., a GPS system, a backup/parking camera orvideo feed), other entertainment components (e.g., a gaming console or apersonal computer), and combinations thereof. Specific features ofoutput side 13 are discussed below in connection with FIG. 3. SWCinterface 10 further can include signal processing components 12, whichcan process SWC signals received at input side 11 prior to outputtingthe signals at output side 13. In various embodiments of the invention,processing of SWC signals by signal processing components 12 can dependupon auto-detections performed at input side 11 and output side 13.

The manner in which SWC signals are auto-detected can depend on theconfiguration of interface 10. For example, if interface 10 isconfigured to auto-detect signals transmitted from a steering wheelcomponent—as may be the case when a vehicle transmits SWC signals usinga variable resistance method—input side 11 can include a wiring harness(not shown), through which interface 10 can be hard-wired to steeringwheel component 14. As another example, if interface 10 is configured toauto-detect signals transmitted on a vehicle bus—as may be the case whena vehicle transmits SWC signals on a bus—input side 11 can include aplug which connects to a jack associated with vehicle bus 16.

FIGS. 2A-C show top-level block diagrams of example circuits capable ofauto-detecting SWC signals. In some embodiments of the invention, thesecircuits may be used individually, while in other embodiments they maybe used combination. As noted above, these circuits can comprise anauto-detecting input side of the SWC interface shown in FIG. 1.

FIGS. 2A and 2B each illustrate a circuit suitable for auto-detectingSWC signals in a vehicle that transmits SWC signals using a variableresistance method. Circuit 21 is one that determines a characteristicvoltage of an SWC channel through the use of a pull-up resistor. Thiscircuit can be suitable for use where the standby resistance of achannel pulls the channel to ground. Circuit 21 includes input port 24,output port 25, processor 26, analog-to-digital (A/D) converter 27, andresistance 28. Input port 24 provides an electrical connection to one ormore SWC channels. Within the circuit, input port connects to resistance28. Resistance 28 can be comprised of a single resistor, a variableresistor, or any suitable circuit element that allows for a voltage onthe SWC channel to be measured. Resistance 28 pulls the output of thechannel up to a voltage V, which can be determined according to designconsiderations and which may be variable. By virtue of resistance 28,the voltage at the input port 24 is a characteristic voltage of the SWCchannel. This voltage is passed through A/D converter 27 and read byprocessor 26. As previously discussed, because the wiring schematics ofsteering wheel components can vary among makes and models, differentvehicles can have different correlations of their characteristicvoltages. Thus, processor 26 can include a recognition module, which candetermine the particular configuration of the vehicle from among knownconfigurations. These known configurations, which can be preprogrammedinto the recognition module, allow the processor to recognize theresistance network of the steering wheel control circuit particular tothe vehicle. In this manner, the variable resistances can beauto-detected and decoded for further processing and transmission an SWCinterface. The output of processor 26, which can include characteristicvoltage readings, resistance determinations, and information relating toa recognized resistance network, is passed to output port 25, which canbe connected to other elements of an SWC interface.

Circuit 22 is similar to circuit 21 except that circuit 22 can besuitable for use where the standby resistance of an SWC channel pullsthe channel up to a particular voltage, e.g., 5 V or 12 V. Circuit 22can be comprised of the same elements as circuit 21 but in a slightlydifferent configuration: circuit 22 differs from circuit 21 in thatresistance 28 pulls the output of the channel down to ground. As incircuit 21, the resistance 28 causes the voltage at the input port 25 tobe a characteristic voltage of the SWC channel. The other elements ofcircuit 22 can perform functions similar to those of circuit 21.

With regard to the circuits illustrated in FIGS. 2A and 2B, those havingordinary skill in the art will recognize that many other circuit designsmay be suitable for detecting a characteristic voltage of an SWCchannel. Although these figures illustrate circuits having both analogand digital elements, suitable circuits may be wholly digital or analog,and may incorporate other elements not discussed herein. Moreover, whencomprising an input side of an SWC interface, there may be many suchcircuits employed. For example, if a vehicle transmits SWC signals overmultiple channels, there may be that same number of individual circuitsincluded in the SWC interface, with one circuit corresponding to eachchannel. Alternatively, there may be only one circuit used, with thecircuit configured to measure a characteristic voltage of each channel.The invention is sufficiently flexible that those having skill in theart will be able to adapt it to any particular designs or applications.

FIG. 2C illustrates a bus-monitoring circuit 23, which can be suitablefor auto-detecting SWC signals in a vehicle that transmits SWC signalson a bus. Circuit 23 includes input port 24, output port 25, processor26, and line receiver 29. Input port 24 provides an electricalconnection to the vehicle bus. Within the circuit, input port 24connects to line receiver 29, which converts vehicle bus signals intologic level signals that are suitable for analysis by processor 26.Output from line receiver 29 is passed is processor 26. Processor 26 ofcircuit 23 can be configured to perform determinations different fromthe processors in circuits 21 and 22. Specifically, based upon theoutput from line receiver 29, processor 26 can auto-detect the bus datarate and the vehicle bus type. Processor 26 further can includehardware, software, or a combination thereof to detect commands presenton the bus and decode those commands that relate to SWC signals. In thismanner, SWC signals transmitted on the data bus can be auto-detected anddecoded by the bus-monitoring circuit 23. The output of processor 26,which can include data relating to any of the information detected,decoded, or determined by it, is passed to output port 25, which can beconnected to other elements of an SWC interface.

Line receiver 29 may be configured in various ways depending on theconfiguration of the vehicle bus. For example, data on a vehicle bus maybe transmitted by single-ended signals or by differential signals.Accordingly, line receiver 29 may be capable of receiving one or moretypes of signals. As another example, electrical signals on the vehiclebus may vary in amplitude; signal swing on one vehicle bus may be 100mV, while on another vehicle bus signal swing may be 12 V. Line receiver29 thus can be capable of converting various signal amplitudes tosignals compatible with logic levels of processor 26. For example, linereceiver 29 may output to processor 26 a 0 V to 5 V electrical signal.

One aspect of the invention is that an input side of an SWC interfacecan connect to vehicle components that transmit SWC signals. Embodimentsof the invention according to this aspect have been described above.Another aspect of the invention is that an output side of an SWCinterface can connect to an aftermarket component and auto-detect thatcomponent. In still another aspect of the invention, an SWC interfacecan deliver SWC signals to an aftermarket component. Embodimentsaccording to these aspects will now be described.

Referring back to FIG. 1, the output side 13 of SWC interface 10 can becoupled to aftermarket component 18 via, for example, a wiredconnection. Most aftermarket components include a wired remote controlinput port at the rear of the component. That input port can acceptcommand inputs from a wired remote control that is either bundled withthe component or sold as an accessory. However, each manufacturer ofaftermarket component uses different techniques to convey remote controlsignals. Thus, prior to SWC interface 10 providing SWC signals toaftermarket component 18, it may be necessary to determine themanufacturer or model of component 18 in order to provide SWC signals ina format recognizable by component 18.

Some aftermarket components utilize a variable resistance method that issimilar to the variable resistance method for conveying SWC signals froma steering wheel component. In this method, a remote control that iselectrically coupled to the input port contains a baseline resistance orvoltage detectable even when the remote control is not being operated,e.g., when none of its buttons is depressed. Each button on the remotecontrol corresponds to a unique change in resistance or voltage in thewired connection from the remote control to the aftermarket componentinput port.

Other aftermarket components utilize a digital waveform method that issimilar to the use of light-emission waveforms for transmitting IRsignals from a wireless remote control, except that the waveforms aretransmitted over a wired connection. Each button on the remote controlis associated with a unique modulation sequence. When a button isdepressed, a pulsed electrical signal generated according to theassociated sequence is transmitted from the remote control to theaftermarket component input port.

Output side 13 can perform an auto-detection of aftermarket component 18by analyzing the electrical characteristics of its input port. Intypical aftermarket components, the input port is pulled up to aparticular internal supply voltage V_(cc) by a particular resistance. Aswith the variable resistance methods for factory steering wheelcomponents, however, there are other input port configurations. Forexample, some manufacturers may design their components such that theirremote control input ports are pulled down to ground. The invention issufficiently flexible that output side 13 can accommodate for variationsin input port electrical characteristics.

One method for analyzing the electrical characteristics of anaftermarket component is to measure the open circuit voltage and theload voltage of the input port. Output side 13 can be configured to makethese measurements. When measuring the load voltage, output side can beconfigured to draw a known current, such as 100 μA. Based upon the twovoltages and the known current drawn, the pull-up or pull-downresistance of the input port can be determined. Using these electricalvalues, output side 13 (or a component to which it can communicate, suchas signal processing components 12) can access a predetermined lookuptable which correlates the electrical characteristics of component 18 toa particular manufacturer and/or model. In this manner, output side 13can determine the particular manufacturer and/or model of theaftermarket component 18, and SWC interface 10 can associate itself witha set of electrical output signals that are correlated to respectiveremote control commands recognized by component 18. Accordingly, whenthe output side 13 receives a control command from input side 11 orsignal processing components 12 indicating input from steering wheelcomponent 14 or vehicle bus 16, the output side 13 can transmit anappropriate electrical signal to aftermarket component 18.

FIG. 3 shows a top-level block diagram of an example circuit capable ofanalyzing the input port of an aftermarket component. This circuit cancomprise an auto-detecting output side of the SWC interface of FIG. 1.The circuit includes port 30, A/D converter 36, processor 37, currentsource 38, and buffer 39. Port 30 can be electrically coupled to theinput port of the aftermarket component. Current source 38 can be variedby processor 37 depending on whether a measurement of the open circuitvoltage or the load voltage is desired. Processor 37 further can varyresistance 38 to control the current drawn through port 30. Analogvoltages from the input port pass through buffer 39 and A/D converter 36prior to reading by processor 37. Processor 37 can read and calculatethe electrical characteristics of the input port. These characteristicscan be sent to other components of an SWC interface, such as signalprocessing components 12.

In various embodiments if the invention, an output side of an SWCinterface can transmit SWC signals to an aftermarket component followingauto-detection of the component. Although transmission of SWC signalscan proceed according to any suitable method, in one embodiment of theinvention, an output side of an SWC interface is configured to transmitboth variable resistance signals and digital waveform signals, dependingon the auto-detection of an aftermarket component. Referring to the SWCinterface of FIG. 1, in this embodiment output side 13 can include avariable resistance circuit and a digital waveform emission circuit.

A variable resistance circuit can include a regulated current sink thatis driven by a pulse width modulated (PWM) output, an output operationalamplifier, and a bipolar junction transistor. The PWM output is coupledto an input of the amplifier, and the output of the amplifier is coupledto the base of the bipolar junction transistor. By increasing ordecreasing the duty cycle of the PWM, the DC voltage at the input of theamplifier is increased or decreased, respectively. Consequently, theamplifier output voltage (and base of the bipolar junction transistor)increases or decreases, which increases or decreases a current at thecollector of the bipolar junction transistor. This current is drawn atthe aftermarket component wired input port by, for example, a pull-downresistor. An increasing current through the pull-down resistor may beinterpreted by the aftermarket component as a remote control commandaccording to its predetermined configuration. While other methods ofreproducing a variable resistance are possible, and may beinterchangeable with the method of the circuit just described, the useof a variable PWM signal can allow for flexibility in variableresistance values.

For transmission of digital waveforms, a digital waveform emissioncircuit can generate a modulated signal pattern replicating a knownpattern corresponding to a particular remote control command for theparticular manufacturer of the aftermarket component. The circuit thencan transmit the signal pattern via the wired link to the aftermarketcomponent using any one of a variety of known modulated signaltransmission techniques.

FIG. 4 illustrates an example method of installing and configuring adevice such as the SWC interface of FIG. 1. The method begins at step401. Prior to this step, an aftermarket component, which may bereplacing a factory-installed component, has been installed in avehicle, and any typical connections, such as power, video, or audioconnections, may have been made. At step 402, an input side of the SWCinterface is electrically connected to the vehicle. Depending on theparticular vehicle in which the SWC interface is being installed, thisstep may include connecting the SWC interface to one or more steeringwheel component wires and connecting the interface to the vehicle's databus. Step 402 may require splicing or cutting factory-installed wiresand may involve proprietary electrical connectors. At step 403, anoutput side of the SWC interface is electrically connected to theaftermarket component. In some instances, the connection may be madesimply by plugging into a jack provided in the aftermarket component.However, in other instances step 403 may require wiring similar to step402. At step 404, other electrical connections are made. Theseconnections may be required for the SWC operate or function properly andmay include, for example, connecting a power wire to the SWC interface,connecting an accessory power wire from the aftermarket component to theSWC interface, or connecting a ground wire from a steering wheelcomponent to the aftermarket component. At step 405, the vehicleconfiguration is auto-detected at the input side of the SWC interface,and at step 406, the aftermarket component configuration isauto-detected at the output side of the SWC interface. Detection at step405 can include auto-detection of a variable resistance network ofsteering wheel components or auto-detection of a vehicle data bus, aspreviously described. Detection at step 406 can include auto-detectionat an input port of the aftermarket component. As discussed below inconnection with FIGS. 5 and 6, if an auto-detecting step is unable tosufficiently identify a configuration of the vehicle or the aftermarketcomponent, the SWC interface can prompt a user to configure the SWCinterface manually. Based on the auto-detection at steps 405 and 406(and any corresponding manual configuration), at step 407 the SWCinterface can internally configure itself to transmit SWC signals to theaftermarket component. The method terminates at step 408.

A set of steps that may comprise steps 405 and 406 is shown in FIG. 5.As shown in this figure, an LED or other indicator on the SWC interfacecan inform a user that auto-detection is in process. When auto-detectingthe vehicle configuration, as would be the case in step 405, the SWCinterface can search for pertinent data or electrical information viaseveral ways, including the vehicle bus and steering wheel components.If the vehicle is sufficiently identified by that data or information,the SWC interface can proceed to auto-detect the aftermarket componentconfiguration. However, if the vehicle configuration cannot besufficiently identified, a user can be prompted to manually configurethe SWC interface with the vehicle information, as discussed below inconnection with FIG. 6A. After the SWC interface has determined thevehicle configuration (whether by auto-detection or manual entry), theinterface can auto-detect the aftermarket component configurationaccording to step 406. If the aftermarket component configuration cannotbe sufficiently identified by auto-detection, a user can be prompted tomanually configure the SWC interface with the aftermarket configuration,as discussed below in connection with FIG. 6B. After the SWC interfacehas determined the aftermarket configuration (whether by auto-detectionor by manual entry), the SWC interface can proceed to indicate thatdetection is successful (and, in the method of FIG. 4, proceed to step407).

FIGS. 6A and 6B show example methods for manually configuring an SWCinterface with a vehicle configuration and an aftermarket componentconfiguration, respectively. As shown in these figures, manualconfiguration can be accomplished through operation of steering wheelcontrol components. Such operation can both program the SWC interface torecognize SWC signals and be used for entry of information. Duringmanual configuration, the SWC interface can provide feedback to the userby, for example, visual indicators such as LEDs.

An SWC interface can be manually configured in ways other than thoseshown in FIGS. 6A and 6B. In some embodiments of the invention, a manualconfiguration routine can be used to alter the assignment or function ofsteering wheel control components. For example, an installer can swap a“seek up” button with a “volume up” button or change a “source” buttonto a “preset” button. Furthermore, such a reassignment or remapping offunctions can be performed by any user of the SWC interface—e.g., aninstaller, a vehicle owner, or a later purchaser of the vehicle—anytimeafter installation and configuration of the SWC interface. Unlikedevices similar to those discussed in the Background of the Invention,some embodiments of the invention can be remapped using only SWC signalsgenerated by SWC components. That is, user input from SWC components,e.g., steering wheel buttons, can be sufficient to remap an SWCinterface; no physical interaction with the installed SWC interface maybe required.

The description has, to this point, related primarily to SWC interfaces.For example, the description has provided embodiments of SWC interfacesthat may be used operate an aftermarket stereo with a vehicle'sfactory-installed steering wheel components. However, as discussedabove, some vehicles may not include such steering wheel components (orthe components may not suitable for use in operating an aftermarketstereo). Another aspect of the invention thus provides aftermarketsteering wheel components that can generate SWC signals and connect to aSWC interface. Example embodiments according to this aspect will now bedescribed.

In various example embodiments, an aftermarket steering wheel componentis a component that is wirelessly connected to an SWC interface. Acomponent configured according to these embodiments includes an RFtransmitter. Using the transmitter, the component can send SWC signalsto an RF receiver that is connected to a SWC interface. The SWC, inturn, relays received signals and/or control commands embodied by thesignals to an aftermarket or factory-installed stereo. In some exampleembodiments, the RF transmitter is battery-powered, and thus thecomponent can be mounted to the steering wheel or steering columnwithout hardwiring. Other embodiments, however, may include some wiringfor electrical power or backup signal transmission. The steering wheelcomponent may be located, for example, directly on the steering wheel ofthe vehicle by any suitable mount. Embodiments of an aftermarketsteering wheel component according to this aspect of the invention arediscussed below in connection FIGS. 7-9.

In other example embodiments, an aftermarket steering wheel component isa component that is hardwired to an SWC interface. In an exampleembodiment, the component is mounted to the steering column and connectsto the SWC interface via wiring that passes through the steering column.The component may be shaped similar to other factory-installed stalks,such as a turn signal stalk or a windshield wiper stalk. Thus, theaddition of the aftermarket component may not contrast visually withfactory-installed components. Embodiments of an aftermarket steeringwheel component according to this aspect of the invention are discussedbelow in connection FIG. 10.

For the sake of clarity and brevity, aftermarket steering wheelcomponents configured according the aspects just described are referredto generally as “RF steering wheel controls” or “RF SWC,” and “stalksteering wheel controls” or “stalk SWC,” respectively. These terms,however, do not limit the features, capabilities, or configurations ofany of the embodiments of those components. As one example, wirelesstransmission by an RF SWC need not occur by RF signals. As anotherexample, a stalk SWC need not be in a similar shape as, or functionsimilar to, a factory-installed control stalk, and it need not belocated or configured on a steering column in a manner similar to afactory-installed stalk.

Generally speaking, an aftermarket steering wheel control, whetherconfigured as an RF SWC or a stalk SWC, includes a housing in which oneor more switches are located. The switches are operable by a user, andthus the housing may further include buttons, toggles, rockers, and thelike, by which the user may operate the switches. Furthermore, a stalkSWC may include a switch actuated by motion of the stalk itself, muchlike a turn signal.

An aftermarket steering wheel control can include several switches forgenerating and/or sending SWC signals to control an aftermarketcomponent (e.g., a stereo). Examples of such switches include “seek up,”“seek down”, “volume up,” “volume down,” and “mode.” “Mode” sends asignal causing the stereo to chance to its source, examples of whichinclude FM radio, AM radio, satellite radio, CD player, MP3 player, andan auxiliary input. “Seek up” sends a signal to the stereo to tune upthe radio, select a next track of a CD, or select a next preset station.Similarly, “seek down” sends a signal to tune down, select a previoustrack, or select a previous preset station. “Volume up” sends a signalto the stereo to increase the volume, and “volume down” sends a signalto the stereo to decrease the volume. Of course, the particularfunctions performed by the aftermarket stereo in response to any ofthese signals will depend on the model of the stereo and itsconfiguration at the time the signal is received.

In various example embodiments, aftermarket steering wheel controlsfurther include switches for operating other features typically found inaftermarket stereos, such as voice recognition and Bluetooth capability.Examples of such switches in these embodiments include “voice,” “onhook,” and “off hook.” “Voice” sends a signal to activate a voicerecognition mode. For example, actuating the “voice” switch may cause aparticular stereo to go into a mode whereby the stereo can respond tospoken user input, and may cause the stereo to play, over connectedspeakers, the phrase “please say a command.” “Off hook” sends a signalto cause the stereo to answer an incoming Bluetooth telephone call, and“on hook” sends a signal to terminate any active Bluetooth telephonecalls. Those having skill in the art will recognize that commandsassociated with the “voice,” “off hook,” and “on hook” switches arepush-to-talk (PTT), hang up (HUP), and pick up (PUP), respectively.

FIG. 7 shows a block diagram of an example RF SWC configured with anexample SWC interface. In this configuration, a RF SWC 710 is wirelesslyconnected to an SWC interface 720 through an RF reception module 721.The RF SWC 710 includes a microprocessor 711 and an RF transmissionmodule 712, which together function as a control module for the RF SWC710. Microprocessor 711 is electrically connected to user-operableswitches (not shown).

RF reception module 721, which is electrically connected to the SWCinterface 720, receives wireless signals transmitted by the RFtransmission module 721 and passes received signals to the SWC interface720. The SWC interface 720 includes a data input module 722 that allowsthe interface to process, pass through, and/or retransmit signalstransmitted from the RF SWC 710. The SWC interface 720 may include othermodules (not shown) that give the interface additional functionality.For instance, the SWC interface can include any of the modules, units,or components of (and be configured in manner consistent with) any ofthe embodiments of the SWC interfaces described above, or it can beconfigured otherwise.

The RF SWC 710, by virtue of its wireless connection to the SWCinterface 720, may be located anywhere a vehicle owner desires, subjectto the constraint that the SWC must be able to communicate with theinterface. In an example embodiment, the RF SWC 710 is mounted to thesteering wheel of the vehicle. Suitable mounts may include, for example,brackets, Velcro fasteners, straps, retaining rings, threaded fasteners,or any combination thereof.

The RF SWC 710 is configured to read the state of the switches using ananalog-to-digital (A/D) converter. When the RF SWC 710 detects that aswitch (or combination of switches) is pressed, it generates a dataframe at the microprocessor 711 and sends the frame to the RFtransmission module 712. The RF transmission module 712 transmits thedata frame using transmission circuitry, which may include an RFoscillator, modulator, amplifier, and loop antenna. In an exampleembodiment, the RF transmission module 712 transmits the data frameusing by modulating a carrier wave using amplitude-shift keying (ASK).

SWC interface 720 receives wireless signals transmitted by the RF SWC710, such ASK-modulated RF signals. In particular, a wireless signal isreceived at the RF reception module 721, which converts it to anon-modulated, or baseband, signal. The RF reception module 721 thenpasses the baseband signal to the data input module 722 of the SWCinterface 720. The data input module 721 analyzes the data frame todetermine which switch (or switches) of the RF SWC 710 was pressed. Upondetermining the switch pressed, the SWC interface 720 sends a signalcontaining an instruction to perform an appropriate function to anaftermarket radio (not shown).

An RF SWC and SWC interface may be configured in a manner other thanthat which is illustrated in FIG. 7 and described above. For example, anRF transmission module can be a component separate from the RF SWC, andthe two components may be connected by an intermediate electricalconnection. When configured this way, the SWC may be mounted or placedin one location of a vehicle (e.g., on a steering wheel, on steeringcolumn, on a dashboard, or in another readily-accessible area) and thetransmission module in a different area (behind a steering wheel, withina steering column, underneath a dashboard, or in another concealedarea). As another example, an RF reception module may be integrated intothe SWC interface. When configured this way, the SWC need not includeneed not include an electrical input, such as wires or a pin connector,or the electrical input can be an alternative input.

A circuit diagram of an example RF SWC, such as RF SWC 710 of FIG. 7, isshown in FIG. 8. In this circuit, the switches 810 of an RF SWC, such as“volume up,” “volume down,” and “mode,” are connected to an integratedcircuit 820. The integrated circuit 820 controls the generation of dataframes and transmission of those frames. Some pins of the integratedcircuit 820 are connected to a loop antenna 830 and an RF crystal 840.Other pins of the integrated circuit 820 may be connected to othercircuit elements and components (not shown). The RF SWC of FIG. 8 may bepowered by a battery (also not shown). Loop antenna 830 transmits RFsignals to a SWC interface such as SWC interface 720 of FIG. 7.

The circuit in FIG. 8 may be configured (and may operate) in thefollowing manner. The switches 810 include a switched resistor arraythat is arranged as a variable voltage divider. That is, when a switchis pressed, the voltage output by the array varies from a nominal valueoutput when no switch is pressed. The magnitude of the variation dependson which switch or combination of switches is pressed. The integratedcircuit 820, to which the resistor array is connected, includes ananalog-to-digital (A/D) converter and an ASK RF transmitter. The A/Dconverter receives the output voltage of the resistor array, its outputquantifies voltage variations resulting from pressed switches. Theintegrated circuit 820, operating according to embedded code, thenassembles a frame—a group of 64 bits—the content of which is based onthe A/D converter output. The bits of the frame are presentedsequentially to the RF transmitter. In this manner, wireless steeringwheel control signals are generated and transmitted by the circuit ofFIG. 8.

One example of an integrated circuit suitable for use in the RF SWC is aMicrochip model number rfPIC12F675F-I/SS. This microchip includes an8-bit CMOS microcontroller and an internal UHF transmitter. Additionaldetails regarding the configuration and operation of the microchip, suchas electrical components and connections and example code, may be foundin Microchip Technology Inc., rfPIC12F675K/675F/675H Data Sheet,DS70091A (2003), the full content of which is hereby incorporated byreference. For example, FIG. 9-5 of the publication shows a schematicfor configuring the microchip to operate as an ASK transmitter.

A circuit diagram of an example RF reception module, such as RFreception module 721 of FIG. 7, is shown in FIG. 9. In this circuit, asurface acoustic wave (SAW) filter 910 receives RF signals through anantenna. The SAW filter 910 eliminates noise in the received signalbefore it is further processed by other components of the circuit. Thefiltered RF signal is then passed to an integrated circuit 920. Theintegrated circuit is connected to an intermediate frequency (IF) filter930, an RF crystal 940, and other circuit elements and components (notshown). The IF filter 930 is used by the integrated circuit 920 todemodulating an input RF signal to baseband. After demodulating theinput RF signal the integrated circuit 920 converts the data framesencoded in the RF signal into electronic signals (e.g., control commandsgenerated by SWC). The integrated circuit then passes the electronicsignals to output. The output may be connected to a SWC interface (notshown), for example.

Examples of components suitable for use in the RF reception moduleillustrated in FIG. 9 include: a Microchip model number rfRXD0420-I/LQmicrochip for component 920; an EPCOS model number B39431B3750U310 SAWfilter for component 910; and a Murata model number SFECF10M7GA00-R010.7 MHz IF filter for component 930. When configured with thesecomponents, the circuit of FIG. 9 functions as an ASKreceiver/demodulator. Additional details regarding the configuration andoperation of the Microchip integrated circuit, and of an RF receptionmodule generally, may be found in Microchip Technology Inc.,rfRXD0420/0920: UHF ASK/FSK/FM Receiver, DS70090A (2003), the fullcontent of which is hereby incorporated by reference. For example, FIGS.3-5 and 3-9 of the publication show schematics for configuring a SAWfilter and for configuring a microchip for ASK applications.

FIG. 10 shows a schematic diagram of an example circuit 1010 for use ina stalk SWC. The circuit 1010 includes an array of switches andresistors. Those having skill in the art will recognize that a stalkSWC, by virtue of circuit 1010, is configured to operate according avariable resistance method, as discussed above in connection with SWCinterfaces. Accordingly, the stalk SWC includes output lines 1020. Inthe example of FIG. 10, the center output line may be connected toground, with the other two output lines being signal outputs. When noswitches are closed (e.g., no buttons on the stalk SWC are pressed),each output line presents a resistance equal to the top resistor ofcircuit 1010. Closing a switch, however, may reduce the resistancepresented to ground on an associated output line. The resistance onthese output lines, when connected to inputs on a SWC interface, forexample, can be used to detect the state of the stalk SWC switches.Specifically, the SWC interface can pull up the output lines with aresistor and quantify the input voltage. Changes in input voltage, then,may be decoded and passed on as SWC signals to an aftermarket component.

The switches included with the circuit 1010 (and contained within thehousing of the stalk SWC) are similar to those discussed above inconnection with those contained within the housing of RF SWC 710 of FIG.7, and thus the circuit 1010 may provide similar functionality in termsof aftermarket stereo control.

In other embodiments, however, a stalk SWC may include circuitry thatperforms functions similar to an RF SWC, as discussed above inconnection with FIGS. 7-9. Specifically, the stalk SWC may includecircuitry that detects whether a switch (or combination of switches) ispressed, and generates and transmits data frames. Unlike an RF SWC,however, a stalk SWC may be electrically connected directly to a SWCinterface. Thus, instead of transmitting data frames wirelessly to theSWC interface, a stalk SWC may transmit such data over a hardwiredconnection.

Because a stalk SWC may be configured to have a direct electricalconnection to a SWC interface, the stalk SWC should be located withinthe vehicle in a position where wiring to the SWC interface exists orcan be placed. In an example embodiment, a stalk SWC is mounted on thevehicle's steering column and wiring to the SWC interface is passedthrough the column. In this example, the stalk includes a threaded endwhich is passed through a hole (either pre-existing or made by aninstaller) in the steering column. Inside the column, a nut is threadedon the end of the stalk, thereby fastening the stalk to the steeringcolumn.

In the foregoing description, example aspects of the present inventionare described with reference to specific example embodiments. Despitethese specific embodiments, many additional modifications and variationswould be apparent to those skilled in the art. Thus, it is to beunderstood that example embodiments of the invention may be practiced ina manner other than those specifically described. For example, althoughone or more example embodiments of the invention may have been describedin the context of steering wheel control components, in practice theexample embodiments may include interfaces that auto-detect vehicle andaftermarket component configurations for the purpose of transmittingsignals other than SWC signals. Accordingly, the specification is to beregarded in an illustrative rather than restrictive fashion. It will beevident that modifications and changes may be made thereto withoutdeparting from the broader spirit and scope.

Similarly, it should be understood that the figures are presented solelyfor example purposes. The architecture of the example embodimentspresented herein is sufficiently flexible and configurable such that itmay be practiced in ways other than that shown in the accompanyingfigures.

Furthermore, the purpose of the foregoing abstract is to enable the U.S.Patent and Trademark Office, the general public, and scientists,engineers, and practitioners in the art who are unfamiliar with patentor legal terms or phrases, to quickly determine from a cursoryinspection the nature and essence of the technical disclosure of theapplication. The abstract is not intended to limit the scope of thepresent invention in any way. It is also to be understood that theprocesses recited in the claims need not be performed in the orderpresented.

1. A method for automatically detecting a configuration of a vehiclecomponent, the method comprising: connecting a control signal interfaceto at least one channel of a first vehicle component, the first vehiclecomponent being one of a steering wheel control component and a vehiclebus; connecting the control signal interface to at least one channel ofa second vehicle component, the second vehicle component being anaftermarket entertainment component; auto-detecting a control signalconfiguration of the first vehicle component, wherein saidauto-detecting includes (i) performing a first measurement on the atleast one channel of the first vehicle component, the first measurementbeing performed by the control signal interface, and (ii) identifying acontrol signal configuration of the first vehicle component based on thefirst measurement; auto-detecting a control signal configuration of thesecond vehicle component, wherein said auto-detecting includes (i)performing a second measurement on the at least one channel of thesecond vehicle component, the second measurement being performed by thecontrol signal interface, and (ii) identifying a control signalconfiguration of the second vehicle component based on the secondmeasurement; and configuring the control signal interface based on atleast one of the auto-detected control signal configuration of the firstvehicle component and the auto-detected control signal configuration ofthe second-vehicle component.
 2. A method according to claim 1, whereinsaid performing a first measurement includes (i) receiving a signaloutput by the first vehicle component at the control signal interface,and (ii) determining one of an electrical configuration of the firstvehicle component and a frame rate of the signal output by the firstvehicle component.
 3. A method for transmitting control signals to avehicle component, the method comprising: a method according to claim 1;receiving a control signal from the first vehicle component at thecontrol signal interface; determining a control command according to thecontrol signal; and transmitting a signal from the control signalinterface to the second vehicle component, wherein the signaltransmitted from the control signal interface includes the controlcommand.
 4. A method according to claim 3, wherein the first vehiclecomponent is a steering wheel control component.
 5. A method accordingto claim 4, wherein the steering wheel control component isfactory-installed and includes at least one user-operable switch,wherein the at least one user-operable switch corresponds to an audiocontrol, and wherein said identifying a control signal configuration ofthe first vehicle component includes identifying the audio controlcorresponding to the at least one user-operable switch.
 6. A methodaccording to claim 4, wherein the aftermarket entertainment componentincludes an audio component, wherein a feature of the audio componentcorresponds to a predetermined control command, and wherein saididentifying a control signal configuration of the second vehiclecomponent includes identifying the predetermined control commandcorresponding to the feature of the audio component.
 7. A control signalinterface comprising: an input unit electrically connectable to at leastone channel of a first vehicle component, the first vehicle componentbeing one of a steering wheel control component and a vehicle bus, andthe input unit being configured to (i) perform a first measurement onthe at least one channel of the first vehicle component, and (ii)receive control signals from the first vehicle component; an output unitelectrically connectable to at least one channel of a second vehiclecomponent, the second vehicle component being an aftermarketentertainment component, and the output unit being configured to (i)perform a second measurement on the at least one channel of the secondvehicle component, and (ii) transmit signals to the second vehiclecomponent; and a signal processing unit connected to the input unit andthe output unit, the signal processing unit configured to (i) identify afirst control signal configuration of the first vehicle component basedon the first measurement, (ii) identify a second control signalconfiguration of the second vehicle component based on the secondmeasurement, and (iii) determine control commands based on the controlsignals received by the input unit and in accordance with the identifiedfirst control signal configuration, wherein the output unit isconfigured to transmit the signals to the second vehicle component basedon the control commands determined by the signal processing unit and inaccordance with the identified second control signal configuration, andwherein the input unit, in performing the first measurement, isconfigured to (i) determine, if the first vehicle component is asteering wheel control component, an electrical configuration of thefirst vehicle component, and (ii) determine, if the first vehiclecomponent is a vehicle bus, a frame rate of the signal output by thefirst vehicle component.
 8. A control signal interface according toclaim 7, wherein the first vehicle component is a steering wheelcomponent.
 9. A control signal interface according to claim 7, whereinthe input unit provides first component information to the signalprocessing unit, the first component information allowing the signalprocessing unit to determine control commands based on control signalsreceived by the input unit, wherein the signal processing unit providescontrol information to the output unit, the control information allowingsignals transmitted to the second vehicle component to be based oncontrol commands determined by the signal processing unit, and whereinthe output unit provides second component information to the signalprocessing unit, the second component information allowing signalstransmitted to the second vehicle component to be recognized by thesecond vehicle component.
 10. A control signal interface according toclaim 7, wherein the output unit, in performing the second measurement,is configured to determine an electrical configuration of the secondvehicle component.
 11. A method according to claim 1, wherein saidperforming a first measurement includes (i) determining, if the firstvehicle component is a steering wheel control component, an electricalconfiguration of the first vehicle component, and (ii) determining, ifthe first vehicle component is a vehicle bus, a frame rate of the signaloutput by the first vehicle component.
 12. A method according to claim1, wherein said performing a second measurement includes determining anelectrical configuration of the second vehicle component.